Vans and minivans have become extremely popular in the past 10-15 years. These vehicles are characterized by having at least one sliding side door which moves on a midpoint track at its rear marginal edge, and two forward tracks, one each at the upper header and the lower sill. In current commercially available vans, the header is on the order of two to three inches in vertical height while the sill is on the order of two to four inches in vertical height. Typically the sill track mechanism is located below the floor level.
Vans have also become the vehicle of choice for disabled persons who require wheelchairs or scooters for mobility. A variety of approaches for effecting the entry of disabled persons into and from these vehicles are available. Primary among them are wheelchair lifts and ramps. In addition, there are vehicle "kneeling" assemblies, which in their most common form, compress the springs of the vehicle on one side or in the front only, so that the vehicle tilts downward towards the passenger entry door to permit easier entrance.
A somewhat different approach is provided by customizing vans in which the floors are lowered on the order of six to eight inches. When combined with either the kneeling feature or motorized bifold ramps, lowered floors provide simple access for wheelchair and scooter users. Alternately, roofs can be raised, but this requires more complex customizing of the door and does not reduce the vertical distance from ground to vehicle floor that the wheelchair must ascend.
One of the serious disadvantages in customizing vans by lowering the floor or raising the top is that the vertical height of the header and the vertical level of the sill are limitations to maximizing the vertical opening height. These add from four to seven inches to accommodate the front arms of the sliding door hardware. Accordingly, by reducing the profile (vertical height) of these elements, one can increase the available total entry height by some four to five inches, which is very significant.
In addition, mounting, adjusting and dismounting conventional sliding or rolling slide doors is difficult because of complicated header and sill roller or slide mechanisms. They are not only difficult to mount and dismount, but also to adjust inwardly and outwardly with respect to the center line of the vehicle to assure proper latching and a tight seal against wind and weather.
Accordingly, there is an unfilled need in the art to have an improved header and/or sill assembly for rolling or sliding type side doors for vans which are lower in profile and permits ease of mounting, dismounting and adjustment.